Abstract
Our goal was to examine the propulsion mechanism of sculling motion by visualising the unsteady flow field around a swimmer's hand using PIV.
One formerly competitive swimmer participated in this study and was instructed to swim using a sculling motion in a swimming flume. Two-hundred series of sequential flow fields around the swimmer's left hand were simultaneously obtained by PIV. The flow fields were calculated from two sequential particle images to determine the particle velocity-vectors and the intensity of the vortices.
A leading edge vortex was found beside the little finger of the hand during the out-scull phase, and the vortex seemed to be shed during the transition phase from out-scull to in-scull. The circulation change around the hand was seen after the transition phase. The results of the present study suggested that the sculling swimmer created a propulsive force induced by the momentum change of the flow field relating to the circulation and the shed vortex.
